Impaired expression of CD26 compromises T‐cell recruitment in human visceral leishmaniasis

An inefficient Th1 response, coupled with skewed Th2 cytokine production, has been implicated to increase susceptibility to visceral leishmaniasis (VL) infection. The expression of the dipeptidyl peptidase Cd26 by polarized Th1 activates a chemokine cascade that recruits Th1 recruitment to the pathologic site. Here, we studied 42 patients with confirmed VL (mean age 24.80 ± 16.26 years; range 3–70 years; 25 males and 17 females), 30 endemic controls, and 10 nonendemic controls. We observed a decrease in constitutive and antigen‐induced expression of CD26 on the T cells of VL patients. Soluble CD26 (sCD26) levels in serum and BM were also found to be significantly lower in VL patients. Following successful therapy, increased sCD26 expression was observed. Tuberculosis pleural effusion derived CCR5⁺CXCR3⁺ effector T cells showed enhanced chemokine‐driven migration in the presence of posttreatment BM aspirate containing high levels of sCD26. Moreover, T‐cell migration could be inhibited by blocking RANTES, IP‐10, and CD26 signaling from the posttreatment aspirate with Ab. Our results indicate that, in VL patients, impaired expression and secretion of CD26 compromises chemokine activation and thus T‐cell recruitment, eventually resulting in a deficient state of local immunity at pathologic sites.     

Soluble CD30 is more relevant to disease activity of atopic dermatitis than soluble CD26

It is suggested that CD30 and CD26 are surface molecules expressed on activated Th2 and Th1 cells, respectively. We examined plasma levels of soluble CD26 (sCD26) and sCD30 in patients with atopic dermatitis (AD) when their eruptions were aggravated and in non-atopic healthy controls, and then analysed the possible correlation between these values and the levels of several clinical markers. The plasma levels of both sCD30 and sCD26 were significantly higher in AD patients than in controls, both in exacerbation status and after conventional treatment. Multiple regression analyses showed that plasma sCD30 was a much better predictor of the levels of serum IgE, serum LDH and plasma sCD25, and the area and the score of AD eruption than sCD26, although elevated levels of both sCD30 and sCD26 are associated with these clinical predictors of AD. Importantly, sCD30 plasma levels decreased significantly in AD patients after conventional treatment, while no significant transition was noted in the concentration of sCD26. Moreover, a significant reduction of sCD30 levels was observed in the group of patients whose eruption score was reduced > 50%, whereas it was not in those < 50%. These findings provide evidence that the successful treatment of AD is associated with down-activation of Th2.     

Soluble CD30 in pediatric patients with atopic dermatitis

Atopic dermatitis (AD) is a chronic, inflammatory skin disease in which a pathogenetic role of Th2 cells has been supposed. This study investigated the presence of soluble CD30 (sCD30), an activation marker of T-cell clones able to produce Th2-type cytokines, in sera from pediatric patients affected by AD ( n =25) with no symptoms of asthma or rhinitis. The severity of the disease was graded by both the SCORAD and Costa et al. clinical scoring systems. Serum levels of sCD30 were significantly higher in patients with AD in respect to both normal donors ( n =20) and urticaria patients ( n = 10), and a positive correlation between serum sCD30 and clinical score was found ( r =0.508; P =0.01) when AD patients were evaluated by Costa et al.'s method. Furthermore, a significant association ( r -=0.443; P =0.027) between sCD30 and serum levels of the soluble interleukin (IL)-2 receptor (sIL-2R) was observed in AD. The presence of high amounts of sCD30 in atopic patients seems to confirm the role of this molecule as an activation marker useful for in vivo evaluation of a Th2 immune response, and the correlation observed with both clinical score and sIL-2R levels indicates the role of sCD30 as an additional marker of disease activity in pediatric patients with AD.     

Soluble CD30 and cyclosporine in severe atopic dermatitis

BACKGROUND: Allergen-reactive Th2-like cells expressing membrane CD30 are present in the circulation of atopic dermatitis (AD) patients during seasonal allergen exposure. Moreover, CD30+ T cells are present in the lesional skin of AD patients and high levels of soluble CD30 (sCD30) are found in the serum of the same atopic patients. To investigate the immunosuppressive capacity of cyclosporin A (CsA) in AD patients, the sCD30 serum level was determined before and after CsA treatment (5 mg/kg/day) in 10 patients with severe, refractory AD. The sCD30 serum levels before and after CsA therapy together with other serum parameters were correlated with disease activity. METHODS: sCD30 serum levels were detected using a commercial sandwich ELISA; serum eosinophil cationic protein (ECP) levels were determined using a radioimmunoassay (RIA). RESULTS: In all AD patients sCD30 serum levels were increased ranging from 36 to 300 U/ml, with a mean value equal to 135.7 U/ml. After 6 weeks of CsA treatment, not only was there a significant difference between serum sCD30 levels before (mean 135.7) and after (mean 96.2) treatment but even the serum ECP levels before (mean 57.78) and after (mean 18.69) therapy showed an important reduction. Moreover, no significant difference was found between the mean of serum IgE levels before and after treatment, although the values showed a correlation (p = 0.0003). No significant correlations could be demonstrated between sCD30 levels and serum IgE or between sCD30 and ECP serum levels nor between sCD30 levels and blood eosinophil count after CsA treatment. Moreover, a positive correlation (p = 0.001) was instead documented between sCD30 and the severity of the disease. CONCLUSIONS: In this study, CsA therapy results in clinical improvement together with a statistically significant reduction in sCD30 and ECP serum levels in AD patients.     

Elevated serum levels of soluble CD30 in patients with atopic dermatitis (AD)

The immunopathology of AD is still unclear, but evidence for an immune response polarized towards Th2 activity has been provided. The CD30 molecule belongs to the tumour necrosis factor (TNF) receptor family and is expressed on activated T cells with a sustained expression in Th2 cells. This molecule also exists in a soluble form (sCD30). Elevated serum levels of sCD30 have been found in patients with Hodgkin's disease, chronic hepatitis B infection and HIV infection. Studies were undertaken to compare the serum levels of sCD30 in patients with AD (n=49) and healthy non-atopic controls (n=94). The presence of sCD30 was analysed with ELISA. A significantly higher concentration of sCD30 was noted in AD patients, median sCD30 level 29 U/ml (range 1–708 U/ml), compared with healthy non-atopic controls (P< 0.001), where the median level was 11 U/ml with a range of 1–1042 U/ml. No correlation was found between sCD30 levels and total serum IgE, or between the AD patients' SCORAD values and concentration of sCD30. sCD30 levels were also analysed in 20 AD patients, which during ketoconazole treatment had improved their clinical scores and reduced their serum IgE and eosinophil cationic protein levels. However, no significant decrease in sCD30 levels was noted after treatment. The results show that patients with AD have elevated levels of sCD30, but without correlation to total serum IgE or disease activity.     

Serum CD40/CD40L System in Graves' Disease and Hashimoto's Thyroiditis Related to Soluble Fas,FasL and Humoral Markers of Autoimmune Response

Activated CD4 T cells' express CD40 ligand (CD154) interacting with CD40 on the B cells surface, protecting them from Fas-mediated apoptosis and in this study, influence humoral response. The aim of the study was to assess soluble CD40 and CD154 in Graves' disease (GD) and Hashimoto's thyroiditis (HT) in relation to Fas and FasL and to the markers of humoral response: aTPO, aTG and aTSHR. The study was carried out in 5 groups of subjects: 1/14 patients with GD in euthyreosis on methimazol (euGD), 2/20 patients with hyperthyroid GD (hrGD), 3/15 patients with HT in euthyreosis on levothyroxine (euHT), 4/16 patients with hypothyroid Ht (hoHT), 5/12 healthy volunteers, age and sex-matched to groups 1–4. The serum levels of CD40, CD154, Fas and FasL, aTPO and aTG were determined by ELISA and aTSHR was determined by the RIA method. CD40 serum concentration was significantly higher in hoHT individuals: 55.8 (24.0–83.2) pg/ml (p<0.01) and euHT patients: 51.2 (20.0–80.1) (p<0.05) as compared to the controls. Also sCD40L values were significantly increased in euHT individuals: 5.1 (1.0–11.8) (p<0.05) and hoHT patients: 3.9 (0.7–11.2) ng/ml (p<0.05) as compared to the controls. There was a positive correlation between sCD40 and sCD154 in the patients studied (r?=?0.36, p<0.001). In HT patients we found positive correlations between sCD40 and aTPO (r?=?0.45, p<0.001) and sFas (r?=?0.36, p<0.05) as well as a negative correlation between sCD40 and FasL (r?=?–0.24, p<0.05). In GD patients there was a positive correlation between sCD40 and aTSHR (r?=?0.28, p<0.05). In summary, our results suggest that CD40/CD154 interaction plays an important role in the regulation of autoimmune humoral response, both in Hashimoto's thyroiditis and Graves' disease. Fas-mediated apoptosis seems to be involved in this process especially in Hashimoto thyroiditis. Soluble CD40 may serve as a marker of the active stage of autoimmune thyroid disease.     

Decreased Dipeptidyl Peptidase IV Enzyme Activity of Plasma Soluble CD26 and Its Inverse Correlation with HIV-1 RNA in HIV-1 Infected Individuals

Human plasma contains soluble CD26/dipeptidyl peptidase IV (sCD26/DPPIV) although its physiological significance remains unclear. To determine whether the plasma sCD26 levels have clinical relevance in HIV-1 infected individuals, the concentration and DPPIV enzyme activity of plasma sCD26 were measured. While there is no significant difference between the plasma levels of sCD26 in 90 HIV-1 infected individuals and in 79 uninfected controls, specific DPPIV enzyme activity of sCD26 was significantly decreased HIV-1 infected individuals (P < 0.0001). Specific DPPIV enzyme activity was correlated with the levels of CD4+ T cells (r = 0.247; P < 0.02), CD8+ T cells (r = 0.236; P < 0.03), and adenosine deaminase (r = 0.227; P < 0.05) and had an inverse correlation with HIV-1 RNA (Spearman's r = 0.474; P = 0.0012). Furthermore, recombinant sCD26 enhanced the in vitro PPD-induced response of lymphocytes from HIV-1 infected individuals with decreased specific DPPIV enzyme activity. These results suggest that the specific DPPIV enzyme activity of plasma sCD26 may contribute to the immunopathogenesis of HIV infection.     

Plasma soluble CD30 level correlates negatively with age in children.

BACKGROUND AND PURPOSE: Atopic diseases are thought to be associated with cytokine-mediated immune dysregulation, for example, a T helper cell type 1/2 (Th1/Th2) imbalance. CD30 is proposed to be one of the surrogate markers for Th2 immunity. In this study, we investigated whether CD30 is a good marker for atopy and Th2 predominance in a pediatric population. METHODS: This study included 61 children with atopy and 27 normal controls. The expression of CD30 on the surface of T and B lymphocytes and soluble CD30 (sCD30) in plasma was determined. RESULTS: There was no difference in the surface expression of CD30 on B or T lymphocytes. Similarly, sCD30 levels in plasma were not different between the 2 groups. Nevertheless, we found a strong negative correlation between sCD30 and age in the control group (r = -0.72, p<0.001; sCD30 = 76.1 - 5.18 x age) as well as in the atopy group (r = -0.45, p<0.01; sCD30 = 61.1 - 3.56 x age). CONCLUSIONS: An inverse relationship was found between age and sCD30 level in children. However, our findings suggest that CD30 is not a good marker for atopic disease and that further studies on sCD30 levels must take age into consideration.     

老年社区获得性肺炎并脓毒症患者sCD14和CD14+/HLA-DR表达及意义

目的 探讨老年社区获得性肺炎（CAP）并脓毒症患者血清sCD14和外周血单核细胞CD14+/HLA-DR表达水平及临床意义。方法 选取2015年1月~2018年12月我院呼吸内科及ICU收治的老年CAP患者126例,根据是否并发脓毒症将老年CAP患者分为脓毒症组56例,非脓毒症组70例,另选择老年健康体检者45例为对照组,脓毒症组根据是否存活分为死亡组30例及存活组26例。采用ELISA法和流式细胞术检测并比较各组血清sCD14及外周血单核细胞CD14+/HLA-DR+表达水平,脓毒症组及非脓毒症组48 h CURB-65评分、28 d死亡率。结果 脓毒症组血清sCD14水平高于非脓毒症组和对照组,而CD14+/HLA-DR+表达水平则低于非脓毒症组和对照组,差异均有统计学意义（P＜0.05）。死亡组血清sCD14水平高于存活组,CD14+/HLA-DR表达水平低于死亡组,差异有统计学意义（P＜0.05）;相关分析显示,血清sCD14水平与CURB-65评分和28 d死亡率呈正相关（r=0.750、0.712,P＜0.05）,而与CD14+/HLA-DR呈负相关（r=-0.692,P＜0.05）,CD14+/HLA-DR与CURB-65评分和28 d死亡率呈负相关（r=-0.653、-0.721,P＜0.05）。结论 老年社区获得性肺炎并脓毒症患者存在免疫失衡,血清sCD14和CD14+/HLA-DR表达水平与CURB-65评分和28 d死亡率密切相关,可作为早期预测感染性疾病病情严重程度和预后的免疫学指标。     

Patterns of serum type 1 and type 2 immune markers in healthy carriers of HTLV-I

Type 1 immunity appears to be diminished in healthy Japanese carriers of human T-lymphotropic virus type I (HTLV-I), but type 2 status remains undetermined. To further examine the subclinical effect of HTLV-I on host immunity, we measured serum antibodies to the Epstein-Barr virus (EBV) in 415 healthy Japanese adults to broadly characterize type 1 status. Levels of the type 2 biomarkers total immunoglobulin E (IgE), soluble CD23 (sCD23), and soluble CD30 (sCD30) were assessed in 167, 142, and 135 of these subjects, respectively. We analyzed the association of HTLV-I with levels of each serum marker using linear and logistic regression. Altered EBV antibody profiles that are consistent with deficient type 1 immunity were more prevalent in HTLV-I carriers than non-carriers (odds ratio (OR) = 2.8, 95% confidence interval (CI) = 1.5-5.3). Carriers also had 45% lower total IgE levels (P = 0.04) than non-carriers. In contrast, HTLV-I infection was not significantly associated with elevated levels of sCD23 or sCD30. These observations are contrary to our expectation of elevated type 2 biomarkers among carriers. We conclude that in this population, healthy carriers of HTLV-I may have subclinical deficiencies in both type 1 and type 2 immunity, and that type 1 and type 2 immunity are not necessarily reciprocal in persons with subclinical immune dysregulation.     

急性冠脉综合征患者血清可溶性CD40L水平的临床研究

目的:探讨可溶性白细胞分化可溶性抗原40配体(sCD40L)和超敏C反应蛋白(hs-CRP)在急性冠脉综合征(ACS)患者发病及预后中的临床意义及机制。方法:根据急性冠脉综合征诊断标准选择86例患者,分为两组:正常对照组(NCHD)17例,ACS组69例,其中不稳定心绞痛(UA)58例,急性心肌梗死(AMI)11例,入院当天采用ELISA测定血清sCD40L浓度和hs-CRP水平。随诊2个月,观察急性心血管事件发生率。结果:ACS组明显高于对照组(P<0.01);AMI组略高于UA组但无统计学意义(P>0.05);sCD40L和或hs-CRP升高组心血管事件较正常组增多。结论:急性冠脉综合征患者早期外周血清sCD40L和hs-CRP水平明显升高,提示CD40/CD40L系统与ACS的发生有关,并与炎症因子C反应蛋白协同,对动脉粥样硬化斑块不稳定性起着重要作用。     

Evaluation of serum levels of soluble CD4, CD8 and beta 2-microglobulin in visceral human leishmaniasis.

The levels of soluble CD4 (sCD4), sCD8 and beta 2-microglobulin (beta 2-M) were measured in sera from patients with visceral leishmaniasis during the course of infection. Levels of sCD4, sCD8 and beta 2-M were raised significantly above levels in normal sera and returned to the normal range after recovery. The decrease in the levels of sCD8 was related to a reduction of anaemia, leukopenia and thrombocytopenia. In contrast, sCD4 levels fluctuated during the period of infection. beta 2-M returned within normal range more rapidly than sCD8 secretion. Our results suggest that T cells are activated during infection, and that it is also possible that the raised levels of these soluble molecules play a role in the impairment of protective immunity.     

An evaluation of serum soluble CD30 levels and serum CD26 (DPPIV) enzyme activity as markers of type 2 and type 1 cytokines in HIV patients receiving highly active antiretroviral therapy.

This study evaluates serum CD26 (dipeptidyl peptidase IV, DPPIV) enzyme activity and serum levels of soluble CD30 as markers of T1 and T2 cytokine environments in HIV patients who achieved immune reconstitution after highly active antiretroviral therapy (HAART). Patients who had experienced inflammatory disease associated with pre-existent opportunistic infections after HAART (immune restoration diseases, IRD) were considered separately. Serum sCD30 levels and CD26 (DPPIV) enzyme activity were compared with IFN-gamma production by PBMC cultured with cytomegalovirus (CMV) antigen in controls and patient groups. High sCD30 levels were associated with low IFN-gamma production after antigenic stimulation in control subjects and, to a lesser extent, in immune reconstituted HIV patients. There was no association between serum CD26 (DPPIV) enzyme activity and IFN-gamma production or sCD30 levels. Serum sCD30 levels and CD26 (DPPIV) enzyme activity were significantly increased in immune reconstituted patients with high HIV viral loads. Patients who had experienced CMV retinitis as an IRD had significantly higher sCD30 levels than all other patient groups. Hence, high sCD30 levels may be a marker of a T2 cytokine environment in HIV patients with immune reconstitution and are associated with higher HIV viral loads and a history of CMV associated IRD.     

In vivo relevance of CD30 in atopic dermatitis

CD30 expression was evaluated by immunohistochemistry in lesional skin biopsies of eight patients with active atopic dermatitis (AD) and three patients with allergic contact (nickel-induced) dermatitis (ACD). CD30 expression was also assessed in a large panel of CD4 + and CDS + T-cell clones generated from the skin biopsies of four patients with AD. Finally, the levels of soluble CD30 (sCD30) were measured in the serum of 41 patients with AD, 19 patients with ACD, and 60 healthy controls. In all specimens of lesional AD skin, where the great majority of infiltrating cells were CD4+ T cells, remarkable numbers of cells were CD30+, whereas virtually no CD30 + cells were found in the skin of patients with ACD. In CD4+ T-cell clones generated from the lesional AD skin, most of which produced both interleukin (IL)-4 and interferon-gamma (IFN-γ) (Th0–like cells) or IL-4 and 1L-5, but not IFN-γ (Th2–like cells), CD30 expression directly correlated with the ability to produce IL-4 and IL-5, but was inversely related to IFN-γ production. High levels of sCD30 (correlated with disease activity: r = 0.618) were detected in the serum of most AD patients, whereas there was no increase of sCD30 levels in the serum of patients with ACD. These data support the view that Th0/Th2–type responses predominate in the skin of patients with AD and suggest that the presence of CD30 + T cells in tissues and/or increased levels of sCD30 in biologic fluids are indicative of Th2–dominated responses.     

Soluble CD26/30 levels before and after treatment with interferon-alpha and ribavirin combination therapy in a pediatric hepatitis C patient.

Chronic hepatitis C virus (HCV) infection frequently leads to end-stage liver diseases and extrahepatic complications. Combination therapy with interferon-alpha (IFN-alpha) and ribavirin is now recommended as the first-line therapy for patients with chronic hepatitis C in adults. However, the benefit of such combination therapy in children with hepatitis C is still under investigation. We report here on a 6-year-old boy admitted with chronic active hepatitis C infection and treated with interferon-alpha and ribavirin. After treatment for 12 months, his serum showed negative HCV RNA, and normal alanine aminotransferase, and there was a sustained response. The patient's serum soluble CD30 (sCD30) level was higher than that of controls (>100 U/mL vs 46 +/- 11 U/mL) before combination therapy but there was no difference in soluble CD26 (sCD26) [103 ng/mL vs 119 +/- 28 ng/mL]. The sCD30 decreased and sCD26 increased at 6 months (45 U/mL and 188.3 ng/mL, respectively) using combined therapy as well as at 4 months after discontinuing it (33 U/mL and 167.8 ng/mL, respectively) in our patient. The results indicate that combined treatment with IFN-alpha and ribavirin may be used as the first-line treatment for children with chronic hepatitis C. The changes of sCD30 and sCD26 may be helpful in estimating of HCV infection activity.     

Elevated levels of soluble CD8 molecule in patients with lymphatic filariasis

The serum levels of soluble forms of suppressor/cytotoxic cells (sCD8) and interleukin-2 receptor (sCD25) were analyzed in 67 patients with lymphatic filariasis and 28 normal controls. Our results show that patients with lymphatic filariasis have significantly higher levels of sCD8 (p less than 0.05) than the control groups, whereas no such difference was observed for sCD25. Within the patient group, however, those in the chronic lymphatic obstruction (CP) had significantly higher levels of both sCD8 (491 +/- 52 U/ml, p less than 0.001) and sCD25 (293 +/- 36 U/ml; p less than 0.02) than those with asymptomatic microfilaremia (sCD8 344 +/- 32 U/ml; sCD25 190 +/- 10 U/ml, respectively). No statistically significant correlation was observed between the serological levels of sCD8 and the percentage of CD8 on peripheral blood T lymphocytes in any of the patient groups. Evaluation of the activation state of B lymphocyte did not reveal any difference in the cellular expression of B7, or serum levels of soluble CD23 in any of the groups studied. Thus the selective increase of sCD8 in patients with filariasis suggests a possible pathogenic role of the cells involved in the release of this molecule.     

Serum soluble CD4 and CD8 levels in Kawasaki disease.

The levels of soluble CD4 (sCD4) and sCD8 in serum correlate with the T cell subset activation and may be important in monitoring and characterizing disease processes during immunological diseases. We compared acute Kawasaki disease (KD) with anaphylactoid purpura (AP) and acute febrile viral infections, such as measles and infectious mononucleosis (IM), in terms of serum sCD4 and sCD8 levels. The levels of serum sCD4 and sCD8 were measured by a sandwich enzyme immunoassay. In addition, peripheral blood mononuclear cell subsets were analysed by single and two-colour flow-cytometric analyses in KD and IM patients. The levels of serum sCD4 and sCD8 were significantly elevated in patients during acute stages of KD, measles and IM, but not AP. Peripheral blood CD4+, CD8+ and also HLA-DR+ T cells count did not increase during the acute stage of KD; however, peripheral blood CD8+ and HLA-DR+ T cell counts were increased during the acute stage of IM. Our results suggest that there is a low level of activation of peripheral blood T cells during acute KD, or that infiltrated T cells in some local tissues of KD patients contribute to the elevated levels of serum sCD4 and sCD8.     

Soluble CD26 Levels and Its Association to Epidemiologic Parameters in a Sample Population

Introduction: Previous studies have suggested the use of soluble CD26 (sCD26) as a tumour marker for the detection of colorectal cancer (CRC) and advanced adenomas. The aim of this study was to assess the sCD26 concentration in a large cohort to evaluate its association to epidemiologic parameters and CRC-related symptoms/pathologies. Subjects and methods: Serum samples were collected from 2,754 putatively healthy individuals with ages ranging from 30–65 years, and with personal or familial history of polyps, CRC and/or CR symptoms. sCD26 levels were measured by ELISA. Results: No association was found between the sCD26 concentration and age (< 50 and ≥ 50), the personal or familial history of polyps or CRC, rectal bleeding, haemorrhoids or diverticula. However, sCD26 was related to non-inflammatory benign pathologies (excluding rectal bleeding, changes in bowel habits, haemorrhoids, diverticula) and to inflammatory benign pathologies. Discussion: Our results confirm that the sCD26 can be easily offered and evaluated in a large cohort. Additionally, the validation of sCD26 as a tumour marker for screening and case-finding purposes requires a further comparison with an established non-invasive test like the faecal occult blood.     

Increased soluble CD14 serum levels and altered CD14 expression of peripheral blood monocytes in HIV-infected patients.

Serum levels of soluble CD14 were elevated in HIV-infected asymptomatic patients or those with lymphadenopathy (CDC II/III) 2.9 +/- 0.8 mg/l compared with normal controls with 2.2 +/- 0.47 mg/l, P < 0.001. A further rise was seen in patients with ARC (CDC IVA) 3.8 +/- 1.1 mg/l, P < 0.01 and patients with AIDS (CDC IVB-D) 5.7 +/- 2.5 mg/l, P < 0.01. Although absolute numbers of CD14+ cells decrease in the AIDS group, the percentage of CD14+ monocytes did not change. In contrast, levels of soluble T cell antigens sCD4 and sCD8, which are higher in HIV-infected patients compared with normal subjects, showed no increase with disease progression. Serum levels of sCD14 were correlated positively with beta 2-microglobulin levels (rs = 0.63, P < 0.0001). Whereas the percentage of CD14+ monocytes did not change, an increase in monocytic CD14 expression in HIV-infected patients was observed (P < 0.01). The percentage of a monocyte subset expressing both CD14 and CD16 increased from 6% in normal healthy persons to 13% in HIV-infected patients (P < 0.001), and did not vary between the HIV patient groups. Incubation of cultured peripheral blood monocytes with azidothymidine had no effect on either normal or LPS-induced or IL-4-inhibited sCD14 release in vitro. Therefore, an effect of AZT on sCD14 serum values in vivo is considered to be unlikely. Our data further provide evidence that monocytes/macrophages are engaged in HIV infection.